Question - Explain Strict Mode in React.
Answer -
StrictMode is a tool added in version 16.3 of React to highlight potential problems in an application. It performs additional checks on the application.
function App() {
return (
);
}
To enable StrictMode, tags need to be added inside the application:
import React from "react";
import ReactDOM from "react-dom";
import App from "./App";
const rootElement = document.getElementById("root");
ReactDOM.render(
,
rootElement
);
StrictMode currently helps with the following issues:
Identifying components with unsafe lifecycle methods:
- Certain lifecycle methods are unsafe to use in asynchronous react applications. With the use of third-party libraries, it becomes difficult to ensure that certain lifecycle methods are not used.
- StrictMode helps in providing us with a warning if any of the class components use an unsafe lifecycle method.
Warning about the usage of legacy string API:
- If one is using an older version of React, callback ref is the recommended way to manage refs instead of using the string refs. StrictMode gives a warning if we are using string refs to manage refs.
Warning about the usage of findDOMNode:
- Previously, findDOMNode( ) method was used to search the tree of a DOM node. This method is deprecated in React. Hence, the StrictMode gives us a warning about the usage of this method.
- Warning about the usage of legacy context API (because the API is error-prone).